1. Field of the Invention
This invention relates to locking electrical plug receptacles and more particularly relates to a locking plug receptacle with easy-to-use plug release means.
2. Description of the Prior Art
A number of female electrical plug receptacles have been developed for use with 110 volt two-prong or three-prong electrical plugs. Plugs are freely insertable and removable from such receptacles. Inadvertent unplugging, though, can cause an undesired loss of power. Further, a receptacle without a plug therein is exposed, and its electrical contacts can be touched by young children who may be injured by shocks therefrom. It is therefore desirable to provide a releasable lock that is reliable and safe to securely hold the plug to the plug receptacle until it is desired to deliberately unlock the plug and remove it from the receptacle. Many inventions have been made in the field of releasable lock mechanisms for plugs. The usage of such plug-locking receptacles is known for use in both wall sockets and extension cords. Most male plugs typically have either a small xe2x85x9 inch diameter hole or a tab near the end of each prong, or a notch or hook on one or more sides of each prong for locking purposes. The prior art includes a variety of examples of how these holes, tabs, notches and hook-shaped elements on the plug prongs may be locked onto and engaged by a plug receptacle, such as taught in U.S. Pat. No. 4,319,797 to Otani et al.; U.S. Pat. No. 4,932,886 to Glaser; U.S. Pat. No. 5,286,213 to Altergott et al.; and U.S. Pat. No. 5,921,799 to Forrester.
The problem with much of the prior art is that the male prongs must be of a specific size or shape to be utilized with a specific locking receptacle. Further, such locking receptacles can become inoperative due to wear of its aligning or directing surfaces, especially when used with somewhat bent or excessively worn plug prongs. Some receptacles with locking mechanisms require not only proper alignment of the prong plug elements, but also further movement and engagement of the locking assemblies in the plug receptacle. Another problem seen in the prior art is that many locking mechanisms of the plug receptacles have control lock parts arranged or protruding from the side of the receptacle which design renders these mechanisms difficult to use for extension cords where a receptacle with an attached plug and cord may need to be dragged across the ground, the floor, over obstacles and the like; and such protruding parts could become caught or entangled.
Another problem found in the prior art is that many receptacle locking mechanisms take some time to interconnect them with the male prongs which situation renders them impractical for widespread use.
Further, a wide range of receptacle locking mechanisms are not hermetically sealed and cannot be hermetically sealed because of their design features.
Many locking plug receptacle designs employ pre-stressed contact assemblies which call for the application of substantial force to be interconnected with the plug prongs. In addition, such assembly of pre-stressed contact planar members with a male prong leads to excessive parts wear, especially when under a current load due to the heat of current arcing.
It is a goal of this invention to provide an electrical plug receptacle with a releasable lock catch mechanism that can be utilized in either an extension cord form or in standard wall sockets and the like.
It is a further object of this invention to provide a plug receptacle can lock and securely hold plugs of any type, whether of the two or three-prong variety, such that no particular modification or specific design is necessary in the plug prong members in order to have the plug receptacle of this device lock and engage the plug therein and when desired, release the plug by deliberate manual maneuvering, as described further below.
It is yet a further object of this invention to provide a plug receptacle that is not subject to wear by friction of the plug parts against interengaging members therewith since the plug parts of this invention engage with the normal contacts on both sides of the flat prong members of either a two or three-prong plug.
It is still a further object of this invention to provide a simplified mechanism for the locking of a plug within a plug receptacle that is convenient and easy to utilize and which can be incorporated into standard plug receptacles for use in wall sockets or alternatively utilized in extension cords or in any other place where plug receptacles are normally utilized.